The invention relates generally to bearings for gun-mounts for shock absorption. In particular, the invention relates to a circumferential array of bearings, preloaded in a gun-mount to absorb recoil, thereby distributing stresses on the gun-mount and reducing overall mount deflection.
Conventional techniques for handling large radial loads involve tapered roller bearings. For example, hubs on automobile wheels use tapered roller bearings to withstand the radial load of such a motor vehicle traveling along a road. Other applications that experience a comparably slower spin rate, such as gun mounts, often employ the use of shims between a mount base and rotating yoke base. As a gun recoils, the radial load transmits through the yoke base into the central azimuth bearing and shims into the mount base.
A disadvantage to this configuration is that the shims do not permit a very stiff joint. As a result, rocking between the shim and the mount base is evident and can lead to high wear rates. One obvious solution involves drastically increasing the size of the azimuthal bearing to minimize deflection from the radial gun fire loads. However, this approach also imposes severe weight and manufacturing constraints.
Conventional techniques for detecting fatigue defects in gun and mortar mounts include inspection of the system after a given number of firings, with mean time between failure being calculated theoretically. With the advent of finite element analysis, theoretical computation of fatigue and mean times between failures has greatly improved. However, due to the complexity of some systems, empirical data provides a more accurate determination of fatigue life.
Outside of gun and mortar mounts, empirical fatigue testing has been conducted for over half a century. This has been limited to material samples, consisting of varying materials, tempers, and environmental conditions. Recently with the increased capability of servo motors and computer control, entire mechanical systems have undergone system level fatigue testing.